Interactive Voice Response system

Interactive Voice Response System (Automation using GSM-DTMF Decoder)

Old is Gold, Old model GSM phones(2 quantity) can be used to make this simple automation project.
Modules required:
Old Model GSM phones (2)
DTMF Decoder Module(1)
Microcontroller(1)
Voice Record and Playback module(1)

 In old mobile phones each key is associated with two frequencies those frequencies can be decoded by using DTMF Decoder. Also to guide user Voice record and playback module is required

1) Old Model GSM phone:
Old Model phone must be configure with following settings
 - Settings->Keypad Tone->set it to maximum value
- Settings-> Enhancement Setting-> set Auto Answer option on headset

2) Voice Record and Playback module:
In this project i used APR33A3 which has 8 channels and can record audio of 1.2Mins duration
record some voice in each channel like instructions
 - Press 1 to turn on Light
 - Press 2 to turn off Light
 etc there is toggle switch to select record/playback mode
while recording select record mode and also each channel is provided with press button
hold particular channel press button to record voice
then change toggle switch to playback mode
and give active low signal to previously recorded channel then you can get recorded voice

3) Interface DTMF Decoder APR33A3 modules to Microcontroller as shown

Call to Mobile phone which is conected to DTMF decoder then automatically it will lift the
call that will activate APR33A3 module that will guide user accordingly  press particular key in
your mobile phone that will be decoded by DTMF decoder. based on that microcontroller has to controll electrical appliances.

download code-here